Let's do some math ..  Rounding examples of 7 random hypothetical purchases:
Case	Tag   Price	Sales   Tax %	Raw Total   Incl. Sales Tax	Rounded   to Penny	Rounded   to Nickel	Rounded   to Dime
Purchase #1	$213.50	7.494%	$229.4997	$229.50	$229.50	$229.50
Purchase #2	$88.98	5.725%	$94.0741	$94.07	$94.05	$94.10
Purchase #3	$89.58	6.178%	$95.1143	$95.11	$95.10	$95.10
Purchase #4	$88.76	3.408%	$91.7849	$91.78	$91.80	$91.80
Purchase #5	$241.44	5.845%	$255.5522	$255.55	$255.55	$255.60
Purchase #6	$40.46	6.547%	$43.1089	$43.11	$43.10	$43.10
Purchase #7	$204.46	5.719%	$216.1531	$216.15	$216.15	$216.20
7 purchase totals =	$967.18		$1,025.2872	$1,025.27	$1,025.25	$1,025.40